A rubber vibration insulator for an automobile, for example, an engaged-type bushing such as a stabilizer bushing or a rear suspension bushing causes noise when launching, sudden breaking, turning to the right or left and the like by a stick-slip phenomenon between a fitting and a rubber bushing surface, in which a countermeasure is required.
As a countermeasure for the above, various methods are studied to lower friction coefficient on the rubber bushing surface. For example, it is employed 1 to add wax in the rubber composition or, 2 add liquid silicone oil in rubber composition or the like.
However, the above method 1 has a problem in that the degree to decrease friction coefficient is not enough, or the effect is only obtained within a very narrow temperature range (at an ordinary temperature) even if reduction of friction coefficient is obtained by adding some kind of fatty acid amide jointly therein. In other words, sufficient reduction of friction coefficient cannot be obtained at a low or high temperature. In the meantime, the above method 2, wherein silicone oil is added therein, has a problem that compatibility with a rubber component is poor, resulting in remarkably poor kneading workability with a rubber compound and a difficulty in mass producing even though it has the superior effect in the reduction of friction coefficient.